What the standard fixes
EN 50291 covers electrical apparatus for the detection of carbon monoxide in domestic premises. It sets out what such a device must do and how that is verified: how it responds to the gas, how quickly it must alarm, how it behaves in conditions that are not the gas, how it signals its own end of life and how it signals a fault.
The parts a buyer can actually read off a listing are the ones this site reports: the sensor type, the stated service life of the device, whether the battery is replaceable or sealed for the life of the unit, whether there is a display, and whether the device announces its own expiry.
That last one matters more than it sounds. Every electrochemical sensor has a finite life, and a device that goes quiet without saying so is worse than no device, because it occupies the place one would have taken.
What it does not promise
It does not make an installation safe, and nothing on this site is described as making anything safe. A detector reports a condition that already exists. It does not prevent the condition, it does not correct it, and it is not an alternative to an installation being right, a flue being clear or an appliance getting its air.
It does not replace a smoke alarm. Those are different devices under a different standard detecting a different thing, and a listing that blurs them is doing a buyer no favour.
And it does not tell you where to put one. Placement is in the manufacturer’s instructions and in the rules where you live, and both are more specific than anything a comparison page could responsibly say.
The documents that sit beside it
Every appliance family on this site, because the appliance is why the family exists. The appliance standards test combustion on a rig; a detector sits in the room where the appliance is actually run.
It also sits beside the German inspection regime, under which the periodic checking of appliance and flue is a legal duty — the point being that a detector is a last line, not a first one, and this site places it accordingly.
Where it appears on this site
On the carbon monoxide alarm family, and cited from every appliance family.
The editorial rule that governs these pages is stricter than anywhere else on the site: a page reports the stated sensor life, the stated service life, the battery arrangement and the standard the maker names, and it stops. It does not compare devices on how protective they are, because that is not a property a data sheet carries.
Questions that keep arriving by post
Does an alarm mean my stove is safe?
No, and this site will not write that sentence about any product. A detector reports a condition; it does not prevent one. Whether an installation is sound is settled by the appliance instructions, the state of the flue and whoever is competent where you live.
Why does a detector expire?
Because the sensor in it has a finite working life, which is why makers state one. A device that stops detecting without announcing it is worse than an empty bracket, and whether a unit signals its own end of life is one of the few things a listing reliably publishes.
Is a sealed battery better than a replaceable one?
They are different arrangements: one ties the battery life to the device life, the other asks the owner to keep up. What the page reports is which arrangement the maker states and what service life it claims, not which is preferable.
Last reviewed 22 September 2026